In a heterogeneous network, there exists a carrier structure in which a control channel, such as Physical Downlink Control Channel (Physical Downlink Control Channel, PDCCH for short), only occupies part of the whole bandwidth of the carrier instead of being extended or mapped to the whole system bandwidth of the carrier as in a Long Term Evolution (Long Term Evolution, LTE for short) system. Based on the carrier structure in which the control channel only occupies part of the whole bandwidth of the carrier, macro base station and low-power base station can use frequency bands that are not overlapped to transmit control channel (including PDCCH or PHICH or PCFICH) and public control channel PBCH or SCH. In LTE system, PDCCH control signalling schedules time-frequency resources used by a terminal for receiving or transmitting data. For a resource allocation type “0”, a minimum granularity for scheduling data resources is a resource block group (resource block group, RBG for short). The RBG size is related to the system bandwidth. Generally, the larger the system bandwidth is, the larger the RBG is. Allocation of each RBG can be indicated using one bit in a resource allocation field in PDCCH, that is, can be indicated in a bitmap manner. With the increase of system bandwidth, the number of bits in the resource allocation field increases, but it does not increase linearly because RBG also increases with the increase of system bandwidth. Physical channels for data transmission include Physical Downlink Shared Channel (Physical Downlink Shared Channel, PDSCH for short) and Physic Uplink Shared Channel (Physic Uplink Shared Channel, PUSCH for short).
For a UE in LTE system Version 8 or 9 (hereinafter, abbreviated as R8 or R9 UE), PDCCH and PDSCH use the same system bandwidth. The size of a resource block group for R8 or R9 UE with the resource allocation type “0” is determined according to the number of resource blocks (resource block, RB for short) contained in this system bandwidth. However, for a terminal such as Version 10 terminal (hereinafter abbreviated as R10 UE), when the new carrier structure is applied, system bandwidths used by corresponding PDCCH and PDSCH can be unequal. If it is still necessary to support both R8 UE and R10 UE or both R9 UE and R10 UE, then the system bandwidth that can be scheduled for data transmission for R10 UE is different from the system bandwidth that can be scheduled for data transmission for R8 or R9 UE on the same carrier. In the prior art, a method for determining the size of a resource block group of UE goes as follows: determining the RBG size of the resource scheduled by the terminal according to the system bandwidth available to the UE as well as the relationship between the system bandwidth and the RBG. Here, for R8 or R9 UE, the RBG size can be determined according to the bandwidth available to the R8 or R9 UE. For R10 UE, the RBG size can be determined according to the whole system bandwidth of the carrier.
Within the system bandwidth corresponding to a common resource area of R8 UE and R10 UE, or within the system bandwidth corresponding to a common resource area of R9 UE and R10 UE, the RBG size for R8 UE and the RBG size for R10 UE may be unequal, or the RBG size for R9 UE and the RBG size for R10 UE may be unequal. Therefore, a scheduler in the base station needs to perform scheduling according to the respective resource block group sizes for different versions of UEs, which makes it complex for the base station to schedule these RBGs and easily results in repeated allocation of resources or waste of resources.